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c# - UWP ListView displays incorrect items upon rapid scrolling when it has a DataTemplate

I have a ListView that is intended to show every product within a database, and it works for the most part, but when I scroll down by dragging the scroll bar, the bottom items end up being incorrect.
XAML Definition:
<ListView x:Name="lst_Products" VerticalAlignment="Top" HorizontalAlignment="Left" Margin="16,124,16,16" Width="300" ContainerContentChanging="lst_Products_ContainerContentChanging" Loaded="lst_Products_Loaded" BorderBrush="Black" BorderThickness="2" CornerRadius="16">
<ListView.ItemTemplate>
<DataTemplate>
<ContentPresenter Content="{Binding Value}"/>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
The data template is present so I can easily grab a product ID number with SelectedValue. According to some trusted community member (or whatever they call the prominent posters) on the MSDN forums said that's the only way to properly show a ListView when the ItemsSource is an ObservableCollection<KeyValuePair<int,RelativePanel>> while having a selectable value member.
The relevant C# code:
private async void lst_Products_Loaded(object sender, RoutedEventArgs e)
{
var products = await ProductManager.GetProducts();
ObservableCollection<KeyValuePair<int, RelativePanel>> productList = new(products);
lst_Products.ItemsSource = productList;
lst_Products.SelectedValuePath = "Key";
}
private void lst_Products_ContainerContentChanging(ListViewBase sender, ContainerContentChangingEventArgs args)
{
if (args.ItemIndex % 2 == 1)
{
args.ItemContainer.Background = new SolidColorBrush(Color.FromArgb(128, 128, 128, 128));
}
else
{
args.ItemContainer.Background = UIManager.GetDefaultBackground();
}
}
public static async Task<List<KeyValuePair<int, RelativePanel>>> GetProducts()
{
var productPanels = new List<KeyValuePair<int, RelativePanel>>();
var productIDs = await SqlHandler.ReturnListQuery<int>($"SELECT id FROM {productTable}");
var productNames = await SqlHandler.ReturnListQuery<string>($"SELECT name FROM {productTable}");
var panels = new List<RelativePanel>();
foreach(var name in productNames)
{
RelativePanel panel = new();
TextBlock productName = new()
{
Text = name
};
panel.Children.Add(productName);
panels.Add(panel);
}
for(int i = 0; i < productIDs.Count; i++)
{
productPanels.Add(new KeyValuePair<int, string>(productIDs[i], panels[i]));
}
return productPanels;
}
The call to SQL Handler just runs an SQL query and returns a list of the results. I can post the code if you need, but I can assure you there's no sorting going on.
A screenshot of what the list looks like. The bottom item should be "Coffee" - Button Test Product 2 is the second item in the list.
A screenshot of the SQL datatable with the "Coffee" product at the bottom where it should be.
In this case it's just the bottom item that's incorrect, however other times it has jumbled 5 or 6 entries near the bottom. This only seems to occur with the DataTemplate/ContentPresenter, but without that, the RelativePanel does not display correctly in the list. Eventually the list will show more information about the product and as far as I can tell, there's no good way to do that without converting the SQL data into a RelativePanel on the c# side.
I'm open to suggestions on solving either the jumbling problem with the template, or adjusting the xaml so that I don't need the template to display bulk sql data without needing the template but I'm at a loss.

c# - UWP ListView displays incorrect items upon rapid scrolling when it has a DataTemplate
The problem should be caused by listview virtualization, There are two ways to sloved this prolbem, one is disalbe listview virtualization by setting ItemsPanel as StackPanel like the following
<ListView>
<ListView.ItemsPanel>
<ItemsPanelTemplate>
<StackPanel />
</ItemsPanelTemplate>
</ListView.ItemsPanel>
</ListView>
And the other way is implement INotifyCollectionChanged interface for your model class. for more please refer to Data binding in depth
It's not good practice that useRelativePanel collection as datasoure, the better way is make RelativePanel in your DataTemplate and bind with mode class property.
For example
<ListView.ItemTemplate>
<DataTemplate>
<StackPanel Orientation="Horizontal">
<TextBlock Text="{Binding Index}" />
<TextBlock Text="{Binding IsItem}" />
<Image Source="{Binding ImageSource}" Visibility="Collapsed" />
</StackPanel>
</DataTemplate>
</ListView.ItemTemplate>

Text block not Updated

I added one text block and bind the first item of array to that text block. I called some API to get the data for that array. But the text block will not be updated when adding values to that array. When calling API it takes some time to get the data, at that time the Text block is rendered. So, After the text block rendered the UI is not updated.
XAML:
<TextBlock Text="{Binding Path=ItemSource[0], UpdateSourceTrigger
=PropertyChanged}" />
View Model:
await this.MyMethod();
this.ItemSource[0] = "Test After";

In order to bind a number of TextBlocks to a modifiable collection of strings, you could easily use an ItemsControl with a view model like this:
public class ViewModel
{
public ObservableCollection<string> Items { get; }
= new ObservableCollection<string>(
Enumerable
.Range(1, 20)
.Select(i => i.ToString())); // or any other initial values
}
The MainWindow constructor
public MainWindow()
{
InitializeComponent();
DataContext = new ViewModel();
}
In XAML use an ItemsControl:
<ItemsControl ItemsSource="{Binding Items}">
<ItemsControl.ItemTemplate>
<DataTemplate>
<TextBlock Text="{Binding}"/>
</DataTemplate>
</ItemsControl.ItemTemplate>
</ItemsControl>
Now something like
((ViewModel)DataContext).Items[0] = "Hello";
would replace the first string in the collection and hence update the ItemsControl.

Data not binding to ListBox WPF

XAML
<Page x:Class="ManufacturingWPF.ShowHardware"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:local="clr-namespace:ManufacturingWPF"
mc:Ignorable="d"
d:DesignHeight="300" d:DesignWidth="300"
Title="ShowHardware">
<Grid Background="AliceBlue">
<ListBox x:Name="HardwareList" ItemsSource="{Binding Hardware}" HorizontalAlignment="Left" Height="122" Margin="76,36,0,0" VerticalAlignment="Top" Width="149">
<ListBox.ItemTemplate>
<DataTemplate>
<StackPanel>
<TextBlock Text="{Binding ID}"/>
<TextBlock Text="{Binding Date}"/>
<TextBlock Text="{Binding Nodes}"/>
<TextBlock Text="{Binding Repeaters}"/>
<TextBlock Text="{Binding Hubs}"/>
</StackPanel>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
</Grid>
Code Behind C#
public partial class ShowHardware : Page
{
public ShowHardware()
{
InitializeComponent();
DisplayData();
}
public void DisplayData()
{
//Datamodel MDM used for ADO and table creation
//Test is a class used to pass the model and as the name suggest
test it
ManufacturingDataModel MDM = new ManufacturingDataModel();
Test t = new Test(MDM);
List<Hardware> x = t.GetHardware();
foreach(Hardware i in x )
{
HardwareList.ItemsSource = i.Hubs.ToString();
}
}
}
}
I'm facing issues binding the data to the listbox as shown in the XAML and code-behind content.
I've tried previous answers without any luck , did my research but apparently I'm missing out something or maybe there is something I don't quite understand.
Itemsource as the name suggest should bind to the source of where my data is being held. In this case the source would be my class Hardware that holds data for Nodes, date , hubs etc etc.
And in the textblock I manually bind these properties and display the values.
But this is not working.
P.S. My DB table is populated.

That's because the ItemsSource is an IEnumerable and you assign to it the list of hardware itself. So you code should look something like this :
ManufacturingDataModel MDM = new ManufacturingDataModel();
Test t = new Test(MDM);
List<Hardware> x = t.GetHardware();
HardwareList.ItemsSource = x;
//or
foreach (Hardware h in x)
HardwareList.Items.Add(h);

This code seems wrong
foreach(Hardware i in x )
{
HardwareList.ItemsSource = i.Hubs.ToString();
}
Then ItemsSource for Binding has to be a Collection (List, ObservableCollecion, IEnumerable<> ...).
Try HardwareList.ItemsSource = x; and remove the foreach loop
I hope this can help you.

Setting binding source properly in XAML

I'd like to have a list of TextBlocks with ComboBoxes next to each of them.
The data source of ComboBoxes should be the same for every ComboBox. Each TextBlock however should contain sequent element of List
Both data source for ComboBoxs and TextBlocks are in my "settings" object. So I set DataContext of the whole window to this settings object.
Here's my problem:
Data source of TextBlock is: List called Fields, which is inside of an object called "Header" of type "Line" (which is of course inside settings object, which is my datacontext).
So, graphically:
settings(type: Settings) - Header(type: CsvLine) - Fields(type: List of string)
Now ComboBox. Data source of every ComboBox should be a List called Tags
Graphically:
settings(type: Settings) - Tags(type: List of string)
I don't know how I should point to these locations, I tried a lot of options, but none of them work. I see just a blank window.
Here's my code:
<Grid>
<StackPanel Orientation="Horizontal">
<ItemsControl ItemsSource="{Binding Headers}">
<ItemsControl.ItemTemplate>
<DataTemplate>
<StackPanel Orientation="Horizontal">
<TextBlock Text="{Binding Fields}"/>
<ComboBox ItemsSource="{Binding DataContext.Tags,
RelativeSource={RelativeSource AncestorType=ItemsControl}}">
</ComboBox>
</StackPanel>
</DataTemplate>
</ItemsControl.ItemTemplate>
</ItemsControl>
</StackPanel>
</Grid>
I have no idea what I should actually pass as ItemsSource to ItemsControl, because I think it should be common source for both TextBoxes and ComboBoxes, but their only common source is settings object - but i already set it as my DataContext.
I have used RelativeSource in ComboBox, but I'm not really sure what it's used for (although I read an article about it on MSDN). I don't know why but it's really hard for me to understand binding - I'm struggling to get anything working.
//EDIT:
Here's my Settings class - which is the type of my settings object:
public class Settings
{
public CsvLine AllHeaders1
{
get
{
return _allHeaders1;
}
}
public CsvLine _allHeaders1 = new CsvLine()
{
Fields = new List<string>()
{
"Header1" , "Header2" , "Header3"
}
};
private List<String> _tags;
public List<String> Tags
{
get
{
return new List<string>() { "Tag1", "Tag2", "Tag3", "Tag4", "Tag5" };
}
set
{
_tags = value;
}
}
}
And here's my CsvLine class:
public class CsvLine
{
public List<string> Fields = new List<string>();
public int LineNumber;
}

So, I'm not 100% sure of what it is you want, but the following should get you started.
Firstly, you need to ensure you bind to public properties - not public members - so the CsvLine.Fields member needs to be changed to public List<string> Fields { get { return _fields; } set { _fields = value; } }. Also not that, if you want changes in the settings object to be reflected in the UI, you will need to implement INotifyPropertyChanged.
Anyway, with this in place and assigned to the DataContext of the grid, the following will display a vertical list of text blocks (showing "Header 1", "Header 2", "Header 3") each with a combo box to the right containing the values "Tag1", "Tag2" ... "Tag5".
<Grid x:Name="SourceGrid">
<ItemsControl ItemsSource="{Binding Path=AllHeaders1.Fields}">
<ItemsControl.ItemTemplate>
<DataTemplate>
<StackPanel Orientation="Horizontal">
<TextBlock Text="{Binding}" />
<ComboBox ItemsSource="{Binding ElementName=SourceGrid, Path=DataContext.Tags}" />
</StackPanel>
</DataTemplate>
</ItemsControl.ItemTemplate>
</ItemsControl>
</Grid>
Hope it helps.

Can I access XAML elements in an array in the codebehind?

I've been looking around but I haven't been able to find anything on this. I am trying to get started making Windows 8.1 apps in C# with Visual Studio 2013 Pro. I want to be able to access multiple elements (particularly buttons or text blocks) in an array because this is more convenient for developing things like board games. For instance, if I were developing tic-tac-toe, I might use a series of buttons like this:
<Grid>
<Button Name="Cell00"/>
<Button Name="Cell01"/>
<Button Name="Cell02"/>
<Button Name="Cell10"/>
<Button Name="Cell11"/>
<Button Name="Cell12"/>
<Button Name="Cell20"/>
<Button Name="Cell21"/>
<Button Name="Cell22"/>
<Grid/>
Now for the function that would check for a win, I would have to check all possible combinations like this is in the code behind:
private bool CheckForWin()
{
if((Cell00 == Cell01) && (Cell01 == Cell02) && isNotBlank(Cell02)) return true;
if((Cell10 == Cell11) && (Cell11 == Cell12) && isNotBlank(Cell12)) return true
...
return false; //if none of the win conditions pass
}
This type of code would be extremely cumbersome. I would like to write it instead in a way that lets me check the array with for loops.
I realize that with tic-tac-toe, it is fairly easy to code it using brute force, but this was the first example that came to my head. Other games like Reversi or Go would not work well like this because of either the sheer size or the fact that pieces placed can change other cells than the one they were placed on.
Any help with this would be greatly appreciated.

This is not the correct way to use WPF. WPF is designed to use data binding....creating and manipulating UI elements directly is bad form. There are more posts/discussion/questions about this than you can imagine and I'll leave you to research them for yourself. In the mean time this is how you use WPF "properly":
First use NuGet to add MVVM lite to your project so that you get the ViewModelBase class and create a view model for a single cell:
public class Cell : ViewModelBase
{
private string _Text;
public string Text
{
get { return _Text; }
set { _Text = value; RaisePropertyChanged(() => this.Text); }
}
}
One level up you'll want a main model to encapsulate an array of these, this is where you will typically do all your game logic:
public class MainModel : ViewModelBase
{
private ObservableCollection<Cell> _Cells;
public ObservableCollection<Cell> Cells
{
get { return _Cells; }
set { _Cells = value; RaisePropertyChanged(() => this.Cells); }
}
public MainModel()
{
this.Cells = new ObservableCollection<Cell>(
Enumerable.Range(1, 100)
.Select(i => new Cell { Text = i.ToString() })
);
}
}
Notice that all I'm doing at the moment is creating a 100-element collection of cells. This main view model becomes the one that you assign to your window's data context:
public MainWindow()
{
InitializeComponent();
this.DataContext = new MainModel();
}
Now your XAML controls need to bind to this data. ItemsControl is used to render a collection of elements so use one of those and bind it to your array. You want them displayed in a 2D grid so replace the ItemsPanelTemplate with a WrapPanel. Finally add a DataTemplate for your Cell class so that a button gets drawn for each cell:
<Window.Resources>
<DataTemplate DataType="{x:Type local:Cell}">
<Button Width="32" Height="32" Content="{Binding Text}"/>
</DataTemplate>
</Window.Resources>
<ItemsControl ItemsSource="{Binding Cells}" Width="320" Height="320" HorizontalAlignment="Center" VerticalAlignment="Center">
<ItemsControl.ItemsPanel>
<ItemsPanelTemplate>
<WrapPanel />
</ItemsPanelTemplate>
</ItemsControl.ItemsPanel>
</ItemsControl>
That's how you use WPF. Your logic is stored entirely in the view model and it's completely decoupled from the view. Here's what this particular code displays, it should be pretty self-evident how flexible this code is and easy to change:

That's very possible. Simply declare an array variable :
private Button[] _buttonArray;
populate the array once, maybe in constructor :
_buttonArray = new[] {Cell00, Cell01, .... , Cell22};
And all of the buttons are now accessible through _buttonArray.